there's a much more elegant solution. Just carry two uninflated paddle floats and a spare paddle, broken down. When you get to your fishing destination, assemble and bungee the paddle across the back, inflate the floats, and there you are. Almost no weight, does not compromise hull design, and if you don't need to use it, you don't bring it.
Since I haven't tried this, it's possible a paddle might not have the right dimensions for the floats to reach the water on either side, so perhaps some clever inventor could design a relatively inexpensive, use-specific brace that would do the job.
Just give me 10% royalty. Thanks!